This invention relates to an apparatus for providing one or more photochemical reactions in imaging materials, In particular, this apparatus is useful to provide photochemical reactions in color or black-and-white photographic imaging materials using a novel photochemical delivery article comprising a hydrogel.
The basic image-forming process of photography comprises the exposure of a silver halide photographic recording material, such as a color film, to electromagnetic radiation, and the chemical processing of the exposed material to provide a useful image. Chemical processing involves one fundamental step and one or more ancillary steps. The fundamental step is treatment of the exposed silver halide material with a developing agent wherein some or all silver ion is reduced to metallic silver, and in the case of color materials, a dye image is formed (because of a color developing agent).
For color materials, ancillary steps include the removal of silver metal and silver salts by one or more steps of bleaching and fixing so that only a dye image remains in the processed material. These steps are commonly used to enable optical printing and can make scanning easier. During bleaching, the developed silver is oxidized to a silver salt by a suitable bleaching agent. The oxidized silver is then dissolved and removed from the material using a xe2x80x9cfixingxe2x80x9d agent or silver solvent in a fixing step. Black-and-white materials are desilvered using only the fixing step.
Additional photoprocessing steps may be needed including rinsing or dye stabilization that requires even more photoprocessing chemicals. In the case of color reversal materials, additional photoprocessing steps include black-and-white development, a reversal step, pre-bleaching or conditioning step and one or more rinsing steps.
All of these photoprocessing steps require preparation of the photoprocessing compositions (whether in aqueous or solid form), large or small photoprocessing tanks or reservoirs to hold the compositions, and disposal or regeneration of the xe2x80x9cspentxe2x80x9d compositions once a predetermined amount of exposed material has been processed. All of these operations require considerable manufacturing effort, shipping and handling of chemicals and aqueous solutions, replenishment of the solutions, and disposal of solutions into the environment. These characteristics of conventional photoprocessing are labor intensive, tedious, costly and potentially harmful to the environment (although much work has been accomplished in the industry to make the compositions more environmentally xe2x80x9cfriendlyxe2x80x9d).
New business opportunities are thought to exist if ways can be found to minimize or obviate the problems described above. Providing photographic images (often known as xe2x80x9cphotofinishingxe2x80x9d) is a growing business and yet there is a need to provide those images in ways that do not require some or all of the traditional photoprocessing solutions, equipment and replenishment systems.
Various research efforts have been carried out in the industry to provide new methods of imaging. For example, research has been carried out directed at putting photoprocessing chemicals directly into the imageable materials. Coated donor/receivers systems on flexible supports have been developed in recent decades for output media (such as color prints). The conventional xe2x80x9cinstantxe2x80x9d photographic materials are examples of imaging materials that include coated and/or delivered photoprocessing chemicals. See for example, U.S. Pat. No. 4,605,608 (Bullitt).
U.S. Pat. No. 5,453,804 (Norris et al) describes a hydrogel, rolled flexible carried material that comprises an aqueous, alkaline processing composition that is used in an image transfer processing method. This material does not include a backing sheet or non-porous supporting substrate.
All of the ongoing research efforts still have some unattractive features pertaining to the delivery of the photoprocessing chemicals (identified as xe2x80x9cphotochemicalsxe2x80x9d hereinafter). To date, the need for enabling technology remains unsatisfied.
Photoprocessing webs comprised of gelatin or other hydrophilic colloids are also known as described for example in U.S. Pat. No. 3,179,517 (Tregillus et al).
In order to simplify the mechanical requirements of photoprocessing, it would be desirable to avoid high precision fluid spreading that may be required in extrusion hopper metering or a fluid bath for coating materials to be laminated. Thus, there continues to be a need for unique equipment or apparatus useful for photoprocessing that is not accompanied by the problems noted above with traditional methods or known research methods. It would also be useful to have such an apparatus that is adapted to process the images in an efficient and simple manner, but that also enables digitization of those images.
An advance in the photographic art is provided with an apparatus for providing a photochemical reaction comprising:
a) a means for supplying an imagewise exposed photographic silver halide material comprising at least one silver halide emulsion layer,
b) a means for supplying a photochemical delivery article consisting essentially of a nonporous substrate having disposed thereon a hydrogel containing one or more diffusible photochemicals,
c) a means for bringing the imagewise exposed photographic silver halide material and the photochemical delivery article into reactive association to form a web laminate so that a photochemical reaction can occur, and
d) a downstream web laminate treating means that is either
i) a means for removing said nonporous substrate from the photochemical delivery article in the web laminate, or
ii) a means for delaminating the photochemical delivery article from the imagewise exposed photographic silver halide material, and a means for collecting the delaminated photochemical delivery article.
Another apparatus for providing a photochemical reaction comprises:
a) a means for supplying an imagewise exposed photographic silver halide material comprising at least one silver halide emulsion layer,
b) a means for supplying a photochemical delivery article consisting essentially of a nonporous substrate having disposed thereon a hydrogel containing one or more diffusible photochemicals, and
c) a means for bringing the imagewise exposed photographic silver halide material and the photochemical delivery article into reactive association to form a web laminate so that a photochemical reaction can occur.
Further, an apparatus for providing a photochemical reaction comprises:
a) a means for supplying an imagewise exposed photographic silver halide material comprising at least one silver halide emulsion layer,
b) a means for supplying a photochemical delivery article consisting essentially of a nonporous substrate having disposed thereon a hydrogel that is substantially free of diffusible photochemicals,
c) a means for bringing the imagewise exposed photographic silver halide material and the photochemical delivery article into reactive association to form a web laminate,
d) a means for removing the nonporous substrate from the photochemical delivery article in the web laminate, and
e) a means for supplying one or more diffusible photochemicals to the photochemical delivery article in the web laminate.
The present invention avoids the need for high precision fluid spreading required for extrusion hopper metering. It also avoids the traditional processing baths and equipment used in conventional photoprocessing and all the problems they entail.
These advantages are provided with the use of an apparatus in conjunction with a novel photochemical delivery article that can be laminated to imagewise exposed photographic silver halide materials to deliver photochemicals for image formation. This lamination operation allows diffusible photochemicals to move into and out of the imagewise exposed photographic materials for a period of time sufficient for desired photochemical reactions to occur. Once the method is finished, the contacted material needs little or no further handling
The photochemical delivery article is a permeable matrix composed of a hydrogel that, in most embodiments, has been impregnated or swollen with one or more photochemicals prior to use. The article can be used to deliver the photochemicals in a controlled fashion to the same or different materials without additional fluid extrusion, pumping or dipping the materials into processing baths. Different delivery articles can be used in sequence to deliver the different photochemicals necessary for the various sequential photochemical reactions required for providing a color or black-and-white image. For example, in providing color negative images, one photochemical delivery article could be used to deliver a color developing agent and one or more other photochemical delivery articles can be used thereafter to desilver the material. Following all necessary processing steps and drying, the processed material either can have a viewable image or be used to provide a viewable image in any suitable fashion.
In some embodiments, the photochemical delivery article is substantially free of photochemicals when it is laminated to the processed photographic material. However, photochemicals can be delivered to the article while it is in the web laminate.
The hydrogel containing delivery articles are advantageous because they readily absorb solvents (containing needed diffusible photochemicals), undergo rapid swelling without discernable dissolution and maintain three-dimensional networks capable of reversible deformation while maintaining their physical and mechanical integrity. Thus, photochemicals can be imbibed into the matrices with minimal effort, and they can be readily absorbed into the imaged materials in the same manner.
The photochemical delivery articles used with the apparatus of this invention are described and claimed in copending and commonly assigned U.S. Ser. No. 09/593,097 filed on even date herewith by Sowinski, Szajewski and Wildman, entitled xe2x80x9cPhotochemical Delivery Article and Method of Use.xe2x80x9d
The apparatus of this invention can be used to advantage in the imaging methods described in copending and commonly assigned U.S. Ser. No. 09/593,089 filed on even date herewith by Sowinski, Szajewski and Wildman, entitled xe2x80x9cMethod of Providing Digitized Photographic Image.xe2x80x9d